This invention relates generally to an apparatus and method to provide a connection for distinct optical channels between at least two optical or electro-optical devices using multiple optical fibers where the connection may have a pre-selected and different channel order at either end of the connection.
In many optical and electro-optical systems (e.g., computer systems, programmable electronic systems, telecommunication switching systems, control systems, and so forth) it is highly desirable to achieve a reliable connection of multiple optical fibers between optical devices. However, achieving such a reliable connection is often difficult. Minimizing the number of optical fiber splices and connections provides advantages because these splices and connections greatly reduce the reliability of the connection between the devices. Hereafter, the term xe2x80x9coptical devicexe2x80x9d is intended to include devices used in the optical and electro-optical systems mentioned above.
Connecting optical devices may require connecting multiple channels between the devices. Each optical device may have a series of distinct optical channels each of which must be connected to a corresponding channel on another optical device. The optical fibers connecting two optical devices are usually incorporated into groups of optical fibers. These groups may be in the form of a ribbon. When connected to an optical device, each optical fiber in a ribbon corresponds to a particular optical channel on the device. For example, referring to FIG. 1, if the group 11 of optical fibers 10 was a ribbon connected to an optical device then each optical fiber 10 within the group 11 will correspond to a particular optical channel e.g., C1-C8 of the device. Also, it is inherent that the group 11 of optical fibers 10 has a respective optical channel order as illustrated by the order of C1-C8. As used throughout this application, the term xe2x80x9coptical channel orderxe2x80x9d defines the order and location/sequence of each distinct optical channel which corresponds to a particular optical fiber in the group. In other words, the optical channel order functionally provides a map both for determining the optical channel that is connected to a fiber in a group, and for determining where that fiber is located with reference to the remaining fibers.
For example, referring to FIG. 1, group 11 is shown with an optical channel order where each optical fiber 10 corresponds to one of channels C1, C2, C3, C4, C5, C6, C7, and C8 in the order and position shown. In comparison, as shown in FIG. 2A, group 1 has an optical channel order 5 where each optical fiber 10 corresponds to one of channels C1, C2, C3, and C4. FIG. 2A also illustrates group 2 as having an optical channel order 6 where each optical fiber 10 corresponds to one of channels C5, C6, C7, and C8.
It is to be understood that the number of optical channels discussed herein is not limited to the number illustrated in the drawings. The number of optical channels may range from 1 to the number required by any particular optical device. For example, a device may have 8, 16, 40, 80, or more optical channels. Moreover, optical channels C1-C8 do not necessarily correspond to channels 1-8 of an optical device. Instead, the use of C1-C8 are simply intended to serve as identifiers for reference purposes.
The development of optical devices with an increasing number of optical channels presents challenges in addition to the need for a reliable optical connection as described above. For instance, it is difficult to physically accommodate an increasing number optical fibers while simultaneously minimizing the space occupied by the optical device. One way of addressing this problem is to reconfigure an optical fiber ribbon to fit more optical fibers within a smaller area. However, reconfiguring the optical fibers in a ribbon will re-arrange the channel order of the ribbon from the proximal end to the distal end of the ribbon. The re-arranged channel order results in an undesirable channel order at the distal end of the ribbon. The problem is significant since suppliers usually sell the optical device with a ribbon already attached. Therefore, in order for a customer to properly connect the ribbon to a second optical device, it is necessary to re-arrange the channel order on distal end of the ribbon. For example, if a first optical device requires a channel order as shown by FIG. 1 and a second optical device requires a channel order as shown by FIG. 2A, but the re-configured ribbon attached to the first device has a channel order as illustrated FIG. 2B, then additional reordering of the optical fibers is required.
Three common solutions for overcoming these problem are described as follows:
(1) Customers can design their systems or devices with a particular channel order at the input/output of the device and use multi-fiber connectors or direct ribbon splices to prevent a mismatch of the channel orders. However, at the time of the filing of this application, there is no discernable industry standard for a channel order for multiple-fiber connectors. The lack of an industry standard may force the customer to change the configuration of their system to accommodate a specific channel order. However, not all customers are able to change the configuration of their system not all customers can change the configuration of their existing systems to accommodate the multiple-fiber connectors. Moreover, it may be difficult to retrofit older systems may to accommodate devices having differing channel orders.
(2) A connector assembly can be spliced onto the input/output fiber ribbon. The connector assembly separates the individual fibers and attaches a connector to each fiber. One drawback to this solution is that splicing a connector assembly onto a fiber ribbon introduces additional splices or connections into the system. These additional splices or connections result in higher insertion loss (signal loss) and, therefore, reduced system performance.
(3) The individual fibers on a reconfigured ribbon of optical fibers may be separated from the ribbon. A connector is then attached to each fiber. However, attaching multiple connectors directly onto individual output/input fibers causes an excessive scrap rate of devices, increases manufacturing time resulting in excessive product lead times, and eventual results in excessive costs for manufacturing the product.
Another solution to the problem discussed above is to re-sequence the ribbon extending away from the first optical device to produce a channel order that is required by the customer. This is accomplished by separating the individual fibers from the ribbon(s) extending away from the first optical device. The individualized fibers are often referred to as xe2x80x9csingulatedxe2x80x9d fibers. Then, the individual fibers are re-sequenced to produce the customer-desired channel order. Next, the re-sequenced fibers are re-ribbonized at the customer-end. Therefore, the customer may splice the fibers to a separate connector assembly to connect the device to their system. Alternatively, the re-ribbonized fibers may be supplied with a connector. While the re-ribbonized fiber may be a desirable solution for some, it may not satisfy the needs of every customer. For example, given the limitations of re-ribbonizing numerous singulated fibers, the re-ribbonized portion may be of a different size than a ribbon that is typically used in the industry. The re-ribbonized fibers may also differ in other characteristics from a standard ribbon such as not being as robust, or not being as flexible. Accordingly, certain customers may require an optical device and ribbon where the channel order matches the customer""s required channel order and the ribbon is not re-ribbonized. Moreover, customers may prefer to directly splice the ribbon from the optical device to their system and may not prefer to use a device with re-ribbonized fibers at the customer-end. Therefore, to address these situations, customers may desire an optical device having an ordinary (or industry standard) ribbon of optical fibers extending away from the device where the ribbon has a customer-desired channel order at the distal end of the ribbon.
There is currently a need to overcome the problems described above. More specifically, while a need remains for maximizing the number of optical fibers and reducing the space occupied by the fibers, there also remains a need to provide an optic fiber ribbon with a customized channel configuration. Such an improved fiber ribbon should minimize the number of connectors and should eliminate the need for the customer to work with the re-ribbonized end of the ribbon.
The invention provides a method and device for selectively reorganizing multiple optical fibers in a ribbon configuration without breaking the optical fibers. The invention also provides an optical system having an optical device connected to a reorganized ribbon of optical fibers.
A first aspect of the invention is directed to an optical system comprising an optical device having a series of distinct optical channels, each of which is connected to a cable assembly.
The cable assembly may comprise a proximal cable portion having a proximal end, a distal cable portion having a distal end, and a transition region separating the proximal portion and distal portion. Each of the optical fibers of the present invention may comprise a core surrounded by a cladding and an outer coating surrounding the cladding along a portion of a length of the fiber. Each of the optical fibers within a cable assembly of the present invention may correspond to a distinct channel. The cable assembly may also comprise a proximal optical connecting region located at the proximal cable portion and adapted to connect the fiber cores to the first optical device. In the proximal optical coupling region the plurality of the optical fibers may be grouped into at least one sub-plurality of optical fibers, where each sub-plurality has a proximal optical channel order defined by the order and position of the optical channel corresponding to each of the optical fibers in the sub-plurality. The cable assembly may also comprise a distal optical connecting region located at the distal portion, wherein in at least a portion of the distal optical connecting region the plurality of optical fibers form at least one ribbon of optical fibers, and wherein each of the ribbons has a distal optical channel order defined by the order and position of the optical channel corresponding to each of the optical fiber in the ribbon.
The cable assembly may also has a transition region of where the plurality of optical fibers are re-ordered from the distal cable portion to the proximal cable portion so that each of the proximal and distal channel orders are different. The transition region may be placed within an enclosure of the optical system.
The invention also includes a method of connecting a first and second optical devices using a ribbon having a proximal end and a distal end and a plurality of optical fibers extending therethrough, the method comprising the acts of removing the plurality of optical fibers from the ribbon at the proximal end of the ribbon; re-ordering the plurality of optical fibers between the proximal and distal ends such that each fiber is in a different from its position in the ribbon; separating said plurality of optical fibers into at least two groups of optical fibers at said proximal end, and connecting each of said optical fibers to said first optical device; re-ribbonizing at least one portion of said proximal end of optical fibers; and connecting the distal end of the ribbon to the second optical device.
The re-ribbonizing step may comprise joining the fibers with a material selected from the group consisting of: tape, polymer, glass, epoxy and metal. The separating step may include interleaving the optical fibers.
These and other objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of the invention and the accompanying drawings.